JP2000027866A - Bearing metal of sliding bearing and manufacture therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the bearing metal of a sliding bearing excellent in an emergency time state and a running-in state together with a high limit load until biting-in of the bearing is caused particularly in a high load range, and a manufacturing method therefor. SOLUTION: The bearing metal of a sliding bearing has a support and at least a single metallic sliding layer. This sliding layer is formed by electron beam evaporation, and the sliding layer has at least a single fine component dispersed in a base material. Atomic weight of this component is larger than atomic weight of the base material. The concentration of a dispersed fine component 7 continuously reduces toward a divided surface range 9 from a top part range 8 of the bearing metal 1 of the sliding bearing. In a method, gas is adjusted to pressure of 0.1 to 5 pa in forming a film of the top part range of the bearing metal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention comprises a support and at least one metallic sliding layer, wherein the sliding layer is formed by electron beam evaporation, and wherein the sliding layer is dispersed in a matrix material at least one. The present invention relates to a bearing metal for a sliding bearing, which has a fine component, and the atomic weight of this component is larger than the atomic weight of a base material. The invention further provides that at least one sliding layer of a metal alloy is formed on the support by electron beam evaporation in the coating chamber, the sliding layer having a fine component dispersed in the matrix material, The present invention relates to a method for manufacturing a bearing of a sliding bearing, wherein the atomic weight of the component is larger than the atomic weight of the base material.

[0002]

2. Description of the Prior Art Sliding elements used in this way generally consist of a multilayer composite system of the following construction. A bearing metal layer consisting of a steel backing metal, a Cu alloy Al alloy or a white metal alloy as a support material and a so-called overlay layer or a third layer or a sliding layer is provided. This sliding layer can be applied by electroplating (E. Roemer: three-way bearing consisting of GLYCO 40; GLYCO Engineers Report 8/67) or by cathodic spraying (sputtering), as described in EP 0 256 226. A coating is formed. In the case of layers based on Pb or Sn, which are mostly formed by electroplating, corrosion resistance is often insufficient or wear-resistant. Furthermore, electroplating is considered problematic from an environmental point of view.

When the overlay layer is formed by a sputtering technique, the cost of the entire sliding element is high because the film formation speed achievable at that time is low and the equipment cost is high.

GB 2270927 shows an aluminum alloy in which the tin content is constant throughout the layer and is between 10 and 80%. As is clear from Table 1 on pages 10 and 11 of this application, as the tin content increases,
It is clear that the critical load increases until the bearing is about to bite. However, the load bearing capacity rapidly drops again from a predetermined tin content. There is no indication in this document to improve the break-in. As a fabrication method for forming an overlay, this application describes sputtering.

[0005] EP 0 376 368 describes a very costly method for producing bearings. This bearing has an advantage that it has good emergency characteristics and smoothing characteristics. This application is again an aluminum-tin-alloy. This alloy is coated by a sputtering process. The main parts of this application are:
The diameter of the particles inserted into the metal substrate of the bearing alloy depends on the static standard distribution, oxygen of less than 0.1% by mass is inserted into the overlay layer, and the microhardness of the overlay layer decreases after heat treatment. This improves implantability, emergency properties and non-biteability.

[0006] WO 91/00375 describes a bearing consisting of a substrate (eg aluminum) having a fine second phase (eg tin) in which an overlay layer is dispersed. Again, sputtering is used.
It is an object of the present invention that the content of the second phase (eg, tin) in the overlay is continuously as a function of the thickness of the overlay layer from 0% at the lowermost position to 100% at the uppermost position. Manufacture bearings with an overlay layer to increase. This is achieved by using multiple targets of different composition and varying sputtering parameters during coating. The overlay layer thus produced exhibits very good properties with respect to wear and fatigue. This is, of course, obtained in a very costly way.

[0007] Published German Patent Application No. 1951
From U.S. Pat. Nos. 4,835 and 195,148, it is known to attach a sliding layer to a concavely curved sliding element by electron beam evaporation. In these documents, formation of a predetermined layer thickness shape is noted. In order to obtain a uniform layer thickness in the case of sliding bearing bearings, DE-A-195 14 835 discloses that during evaporation of the sliding layer, the evaporator and the support are relatively linear at different speeds. Go to For that purpose, a suitable adjusting device is required in the coating room. On the other hand, in the case of DE-A-19514836, the non-uniform layer thickness is adjusted appropriately. The layer thickness of the sliding element is at most maximum in the top region and decreases continuously towards the dividing plane. To achieve this, the method requires that the distance from the evaporator to the top area of the bearing metal of the plain bearing be 150-350.
mm, the evaporator and the support are positioned so as to be stationary with respect to each other during the deposition of the layer, and the condensation rate for deposition in the top area is adjusted to at least 80 nm / s.

[0008] Published German Patent Application No. 3606
No. 529 discloses a method for producing a layered material or a layered workpiece by depositing at least one metal material on a metal substrate. In the case of this method, an electron beam evaporation method for forming a slide layer is similarly used. The process is carried out in a residual gas atmosphere at a pressure in the range from 10 ^-2 to 10 ^-3 mbar. In this case, the material is simultaneously diffusion hardened or diffusion hardened by vapor deposition. A stratification rate of about 0.3 μm / s results. During deposition, the substrate is kept at a temperature of 200-800C. During the deposition of the aluminum alloy, the temperature of the substrate is about 200-300 ° C.
The range is from 00 to 700 ° C. The load carrying capacity of the layers produced according to this method is much better than the layers produced by powder metallurgy. In the case of this application, it has been noted that a predetermined proportion of the main layer is generated in the sliding layer during the deposition, for example by diffusion fixation by generating oxides.

[0009] The three references do not suggest distributing the alloying components differently. For some applications, the load-bearing or level-up condition is not sufficient.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a bearing for a sliding bearing which has a good emergency condition and a good break-in condition, particularly in a high load range, with a high limit load until the bearing bites. It is to be. It is also an object of the present invention to provide a low-cost method based on electron beam evaporation for producing bearings for such sliding bearings. This method simply ensures a uniform layer thickness over the entire circumference of the bearing.

[0011]

SUMMARY OF THE INVENTION In a bearing of a sliding bearing, the concentration (density) of dispersed fine components continuously decreases from the top region of the bearing of the sliding bearing toward the division surface. It is characterized by being.

The sliding layer thus constructed has the advantage that in the highest load range, that is, the top range, the alloy component which determines the emergency state and the smoothing state has the highest concentration. Another advantage is that the relatively finely dispersed fine components are only present in a high concentration range. In this range, this component is particularly necessary for emergency and leveling processes.

Since the sliding characteristics in the highest load range determine the life of the entire slide bearing, the life can be extended by increasing the concentration of the distributed fine alloy component in the top region.

The concentration of the dispersed fine components in the top region is, in particular, 1.2 to 1.8 times, preferably 1.3 to 1.6 times, the concentration in the dividing plane region.

According to the first embodiment, the concentration of the dispersed fine components is constant over the thickness of the sliding layer.

According to a second embodiment, the concentration distribution in the circumferential direction can be combined with different concentrations over the layer thickness. In this case, in particular, the concentration of the dispersed fine components increases continuously from the lower region of the sliding layer, ie from the side near the support to the upper region. This embodiment of the sliding layer
It is selected when the rotating body which is the counterpart of the bearing of the plain bearing has a large surface roughness, for example, in the case of a cast shaft.

The concentration of the dispersed fine components is preferably such that the upper region of the sliding layer is less than twice the lower region.

The concentration of the finely dispersed component is preferably from 10 to 70% by weight in the top range.

The matrix material is in particular made of aluminum, in which case the finely divided component consists of tin, lead, bismuth and / or antimony. The sliding layer has up to 5% by weight of other alloy components, individually or in combination, of copper, zinc, silicon, manganese and / or nickel.

As the support, a steel backing, a steel / CuPbSn composite, a steel / aluminum composite or a steel / white metal composite can be used. Preferred alloy systems for forming the sliding layer are AlSnCu, AlSnPb and AlSnSi. In the case of a sliding layer made of a tin alloy, the percentage of tin in the sliding layer decreases from the top of the sliding element toward the dividing plane. That is, the sliding layer has a range in which the proportion of tin is large and a range in which the tin ratio is small. Only then can the advantages of a high tin content and a low tin content be simultaneously available in the sliding layer. A range with a high tin content guarantees a good running-in of the sliding element, and a range with a low tin content guarantees a high load-carrying capacity of the sliding element.

The thickness of the sliding layer is particularly uniform over the entire circumference.

In a method for producing such a sliding layer of a bearing of a sliding bearing, a method of depositing the top area of the bearing during the deposition is as follows.
The gas is adjusted to a pressure of 0.1-5 Pa.

The gas molecules between the evaporation crucible and the surface to be coated are subject to different scattering (diffusion) of the alloy components during the deposition process.
Is generated.

In this case, the scattering angle or degree of scattering is
For dynamic reasons, it depends on the specific gravity of the evaporated individual alloy elements. As a result, heavy elements such as tin are scattered more strongly than light elements such as aluminum. As a result of this scattering process, heavy elements are deposited at a higher concentration in the top region of the bearing metal of the plain bearing than in the split surface region. This scattering of gas molecules allows the composition of the overlay to be varied within wide limits, depending on what pressure range is used in the case of electron beam evaporation.

The layer formed by gas scattering is surprisingly, contrary to expert opinion, compact and its properties in terms of abrasion resistance and load-carrying capacity are reduced by conventional sliding elements or without additional measures. Better than sliding elements made by electron beam evaporation.

It is further surprising that, besides the various density adjustments, a uniform layer thickness is produced at the same time, so that no additional measures such as are known from DE-A 195 14 835 are necessary. is there.

This greatly simplifies the manufacturing method.

The gas pressure during the coating process is in particular ± 0.05
It is kept constant at Pa. This method can be modified by a continuous change in gas pressure during the coating process.
When the gas pressure varies with the function of the deposition time, deformations of the composition can be achieved over the layer thickness, as well as the deposition structure of the sliding layer in the circumferential direction.

In particular, the gas pressure is set at 0,1 at the start of the deposition process.
It is continuously increased from 1 Pa to 1 Pa at the end. Due to the increase in gas pressure, low atomic weight alloy components are scattered more strongly than heavy alloy elements. Thereby, the difference in density between the top area and the split plane area increases over the course of the process. Thus, the concentration of the composite component varies over the layer thickness.

As the gas, a rare gas such as argon, helium or neon is preferably used.

At this time, the vertical distance of the bearing metal of the sliding bearing from the evaporating crucible is adjusted to 2 to 7 times the diameter of the bearing metal, and the film forming speed in the top region is adjusted to at least 20 nm / s.

[0032]

Next, the present invention will be described in detail with reference to embodiments and drawings.

FIG. 1 shows a bearing 1 of a sliding bearing having a support 2 and a sliding layer 6. The support 2 comprises a steel backing metal 3. On this steel backing metal, CuPbSn
An alloy 4 is provided by a casting or sintering process, and a diffusion blocking layer 5 is provided. The carbon content of steel is 0.
03-0.3%.

After the various annealing and deformation processes known per se, the strip is cut into strips of a predetermined length and the strips are pressed to form the bearing metal of the plain bearing. Is produced. After the bearing has been surfaced by drilling or rolling, a diffusion blocking layer 5 of nickel or a nickel alloy is formed on the bearing metal by an electroplating process or a PVD process. Thereafter, the support is degreased and placed in a vacuum evaporation apparatus. Here, a further surface cleaning or activation is performed by means of a spray etching process.

After exhausting the film forming (coating) chamber, argon is supplied to the film forming chamber. In this case, the pressure is adjusted to about 1 Pa. Subsequently, the support 2 is formed by electron beam evaporation of AlSn20Cu from an evaporation crucible using an axial electron gun. The layer thickness of the coated AlSn20Cu sliding layer 6 is about 16 ± 4 μm.

During the deposition process, the argon pressure is about 1 P
a, and the temperature of the support is about 190 to 200
° C, and the power of the electron gun was about 40-60 kW. The deposition rate was at least 20 nm / s.

The sliding layer 6 has a much higher tin concentration in the top region than in the split surface region 9. Tin particles are indicated by point 7. The high density is indicated by the high dot density in the top region 8.

FIGS. 2 and 3 show the composition of the alloy in the top region (FIG. 2) and the split plane region (FIG. 3). Tin content was measured for a given area of the deposited AlSn20Cu layer by EDX with a scanning electron microscope. The tin concentration in the top area 8 was 1.4 times the split plane area. In this case, the value was calculated by integration over the tin peak.

FIG. 4 shows the critical load obtained by an Underwood inspection stand of a bearing metal according to the invention made with a deposited overlay layer, in direct comparison with conventional three- and two-part bearings. Is shown. In this test, an aluminum binary bearing (rod A) having a sliding layer of AlSn20Cu was selected as the basis (10).
0%). The binary bearing (rod B) based on AlSn enables high load bearing. The base material of this dual bearing is reinforced by alloy elements nickel and manganese. A three-way bearing (rod C) with a steel / copper and lead alloy / plated layer (PbSn10Cn5) structure can withstand the loads between the aforementioned two-way bearings. As shown in FIG. 4, the load bearing capacity of the sliding bearing (rod D) deposited according to the present invention is greater than that of the conventional bearing.

[Brief description of the drawings]

FIG. 1 is a perspective view of a bearing metal of a slide bearing.

FIG. 2 is a graph showing the alloy composition of the sliding layer in the top region.

FIG. 3 is a graph showing an alloy composition of a sliding layer in a division surface area.

FIG. 4 is a graph showing a critical load obtained by an underwood test of a bearing metal of a sliding bearing having a sliding layer manufactured according to the present invention, as compared with a conventional three-way bearing or two-way bearing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bearing metal of slide bearing 2 Support body 3 Steel backing metal 4 CuPbSn layer 5 Diffusion prevention layer 6 Sliding layer 7 Tin particles 8 Top area 9 Division plane area

 ──────────────────────────────────────────────────続 き Continuing the front page (72) Inventor Jens-Peter Heins Germany, 01157 Dresden, Sonnenlehne, 21 (72) Inventor Christoph Metzner Germany, 01474 Parplitz, Birkenstrasse, 9

Claims (15)

[Claims] 1. A method comprising: providing a support and at least one metallic sliding layer formed by electron beam evaporation, the sliding layer having at least one fine component dispersed in a base material; In the bearing metal of the sliding bearing, in which the atomic weight of this component is larger than the atomic weight of the base material, the concentration of the dispersed fine component (7) is increased from the top range (8) of the bearing metal (1) of the sliding bearing. A bearing metal for a sliding bearing, characterized in that the bearing metal decreases continuously toward the division surface area (9). 2. The concentration of the dispersed fine component (7) in the top region (8) is 1.times. The concentration of the divided surface region (9).
The bearing of claim 1, wherein the ratio is 2 to 1.8 times. 3. The bearing metal according to claim 1, wherein the concentration of the dispersed fine component (7) is constant over the thickness of the sliding layer (6). 4. The slide according to claim 1, wherein the concentration of the dispersed fine component increases continuously from the lower range to the upper range of the sliding layer. Bearing metal for bearings. 5. The sliding bearing according to claim 1, wherein the concentration of the dispersed fine component (7) is from 10 to 70% by weight in the top region (8). Bearing metal. 6. The concentration of the dispersed fine component (7) in the upper region of the sliding layer (6) is 2% of the concentration in the lower region.
The bearing metal of the sliding bearing according to claim 4 or 5, wherein the diameter is not more than twice. 7. The material according to claim 1, wherein the base material is made of aluminum and the dispersed fine component (7) is made of tin, lead, bismuth and / or antimony.
The bearing of the sliding bearing according to any one of claims 6 to 6. 8. The sliding layer (6) may comprise, as another alloy component,
8. The bearing metal of the sliding bearing according to claim 1, comprising copper, zinc, silicon, manganese and / or nickel individually or in combination up to 5% by mass. 9. 9. A bearing according to claim 1, wherein the thickness of the sliding layer is uniform over the entire outer periphery. 10. At least one sliding layer made of a metal alloy is formed on a support by electron beam evaporation in a coating chamber, and the sliding layer has fine components dispersed in a base material. In a method for making a bearing of a sliding bearing, wherein the atomic weight of the component is greater than the atomic weight of the base material, a gas of 0.1 to 5 Pa is applied during the coating of the top area of the bearing.
Adjusting the pressure to a predetermined value. 11. The method according to claim 10, wherein the gas pressure is varied continuously during the deposition process. 12. A gas pressure of 0.1 at the beginning of the deposition process.
The method according to claim 11, wherein the pressure is continuously increased from Pa to 1 Pa at the end. 13. A rare gas, such as argon,
13. The method according to claim 10, wherein helium or neon is used. 14. The method according to claim 10, wherein the vertical distance of the bearing metal of the sliding bearing from the evaporating crucible is adjusted to 2 to 7 times the diameter of the bearing metal. . 15. The coating rate in the top region is at least 20.
2. The method according to claim 1, wherein the wavelength is adjusted to nm / s.
5. The method according to any one of 4.